Carbon dioxide credits are fetching about 60 cents a metric ton, down from a high of about $7 a year ago, according to the National Farmers Union, which runs the program.
"We're just kind of treading water at this point," said Roger Johnson, president of the National Farmers Union and former North Dakota agriculture commissioner.
Farmers, ranchers and landowners earn credits by growing grasses and trees or using no-till farming practices, in which seeds are injected into the soil to reduce the amount of dirt turned over and carbon released. Livestock producers can participate by installing systems to capture methane from manure.
The program pools the credits for sale on the Chicago Climate Exchange, a private agency that trades greenhouse gases and other pollutants just as other exchanges trade commodities such as crops and livestock. Corporations, cities and other exchange members buy the credits to help offset their emissions.
About 3,900 farmers and ranchers in 40 states are enrolled in the program, with about a quarter in North Dakota, where it began three years ago, said Dale Enerson, director of the National Farmers Union program.
The program's participants in 2006 and 2007 captured carbon dioxide from 2.8 million acres, or about the amount produced by 320,000 cars per year, Enerson said.
Farmers usually receive payment for their credits - typically a few thousand dollars - in July. But those checks haven't been sent this year because most of the carbon credits pooled in 2008 have yet to be traded, Johnson and Enerson said.
Enerson said some companies that had participated in the program have shuttered due to a harsh economy.
"Some of their factories have been closed, so they are emitting less or not at all," he said. "So there is no need for an offset."
The program costs about 70 cents a metric ton to run, or about a dime more than what carbon dioxide credits are now fetching, Johnson said. That would leave farmers with almost nothing if the credits were sold.
Instead, the program is holding off on selling the credits, which are good until traded and used.
There's hope the market will bounce back if Congress passes legislation limiting how much carbon dioxide power plants and other major polluters can release. But it's unclear whether agricultural credits will be included in the final bill, Johnson and Enerson said.
"The market is fairly low right now," Enerson said. "But farmers know that grain in the bin could be worth more in the future."